Triple valve.



W. C. WEBSTER.

TRIPLE VALVE.

APPLICATION EILBD JULY 1o, 191s.

wm C? M' 1HE MORRIS PETERS Co.. FHorL/THU.. WASHINGTDN, L; C.

C. WEBSTER.

TRIPLE VALVE.

APPLICATION FILED JULY 10, 1913.

Patented Nov. 17, 1914.

2 SHEETS-SHEET 2.

l/'gf. 6' J9 26- 2,2 l 37 Y \//4/ 2V V 3 W y Umm THE NORRIS PE TERS C01, PHON-LITHU.. WASHINGTON. D4 C.

. UNITED sTATEs PATENT oEEicE.

WILLIS C. WEBSTER, OF DUBOIS, PENNSYLVANIA, SIGNOR TO BUFFALO AIR BRAKE COMPANY, OF BUFFALO, NEW YORK, A CORPORATION OF, ARIZONA.

TRIPLE VALVE. v

To all whom it may concern Be it known that I, lViLLis C. lWEBsTER, a citizen ofthe United States, andresident of Dubois, in the county of Clearfield andState of Pennsylvania, have invented certain new and useful Improvements in Triple Valves,

of which the following is a specilication.

This invention relates to triple valves ofv tion to vent the brake cylinder through said retaining valve to holdv the brakes applied with reduced pressure, and to recharge the auxiliary reservoir while the reduced brake cylinder pressure is held by the retaining valve. Then the auxiliary reservoir has been recharged to the same pressureas ,the brake pipe pressure, the triple valve moves to full release position in consequence of equalizing the auxiliary reservoir pressure and brake pipefpressure. The movement to full release position causes a complete exhaust from the brake cylinder and fully releases thev brake. The movement of the triple valve from service lap directly to full release position orto retaining' valve position is optional with the engineer, a relatively slight increase of lbrake pipe pressure beine' effective for causinfa full release of brakes withoutbringing 'into operation the retaining valve, while a relatively great increase of brake pipe pressurecauses the triple valve to move to retainingvalve position. l i

Another feature of the invention is an equalizing device which is adapted to perform the same functions as the usual leakage groove in the bushing of the triple valve piston, for maintaining equalization of the brake pipe4 pressure and ofthe auxiliary reservoir pressure. My improved equalizing device dispenses with the aforesaid leakage groove and is more effective, first, because it renders the triple valve more sensitive, and second, because it prevents the es` Specification of Letters Patent.` y Application filed July 1D, 1913. Serial No. 778,304. f

Patented Novi-17,1914.

cape of auxiliary reservoir air back into the bra-ke pipe when the brake pipe .pressure is necessary .with triple'valves which have'the leakage groove in the piston bushing.

Of the accompanying drawings, which illustrate the invention: Figure 1represents a longitudinal section ofl ay triple valve whose main piston and slide valve `are in service position, this vfigure including a portion of an auxiliary reservoir andbr'ake cylinder feed pipe. Fig. 2, on a largerscale, is a vertical sectionincluding .a slide valve,'its. bushing, a graduating valve,H and an vadjacent portion of thevalve casing.- i Figi?) is a sectionsimilar to Fig. 2, showingthe slide valve in position to reducebut not exhaust tliebrake cylinder pressure. Fig. i4 represents a horizontal section including the slide f valve bushing and adjacent portions ofthe main casing. Fig. 5 represents ahorizontal. sectionthrough the slide valve, near the bottom. Fig. 6 is a vertical cross section of the triple valve with itsv attachments.. Fig. 7,. on a larger scale, is a vertical sectionin-the-A saine plane as Fig. '6, showing' valve mechanism which is omitted from Fig. 6. Fig. 8 is a vertical'ci'oss section through the brake cylinder supply valve shown at the right of Fig. 6,-F ig. 8 showing'tlie brake cylinder supply passageway extending from the `supply valve to the slide valve bushing. Fig.

9 is alongitudinal vertical section through,

the main slide valve and its bushing, showing the brake cylinder feed passages, the position ofthe slide valve being the same as.`

in Fig. 41. i

The sainereference characters indicate the same parts wherever they occur. l

The general structure and operation of the triple valve, except as otherwisespecilied, areV standard, and reference is hereinafter made to U. S; Letters Patent 1,040,070, granted-Q October 1, 1912, to Webster et al., which patent shows a brake cylinder supply valve similar to the one included in- Figs. 6 and 8,

i of this application.

rThe triple valve includes the usual maincasing 10, slide valve Abushing `11, main pisi011 .bushing 12, brakeripe @timber 13; and

emergency equipment including piston 14, valve 15 and check valve 1G. T he casing of the chamber 13 is provided with a nipple 17 for connection with the usual brake pipe (not shown). The usual auxiliary reservoir is indicated at 1S, and the brake cylinder lfeed pipe is indicated at 19.

A slide valve, indica-ted at 20, is provided with the usual graduating pin valve 21 and passageway 22 controlled thereby for conducting air from the auxiliary reservoir to the brake cylinder when the slide valve is in service position. The graduating valve is actuated, as usual, by a main piston 23. lllhen the slide valve is in service position, as shown by Figs. 1 and 9, air passes from the auxiliary reservoir through passageway 22 and through brake cylinder' feed port 9.4L of the slide valve bushing and thence through passageway 25 to the pipe 19. The slide valve includes a passageway 26 by which air is conducted directly from the brake pipe to the brake cylinder for general service application. This passageway 26 is smaller than that which conducts air from the auxiliary reservoir to the brake cylinder. ln this respect the slide valve is similar to that shown in the aforesaid patent to Webster cz*- aZ., 1,010,070. is shown by Fig. 9, the delivery end of passageway 26 communicates with passageway The receiving end of passageway registers with a port 27 in the bushing 11. This port is at the delivery end of a feed passageway 28 (see Fig. S), the receiving end of said passageway communicating with a chamber 29 of a brake cylinder supply valve 30. This valve is closed by a spring 31 and by pressure in chamber 32, and is opened by a spring The stem of the valve 30 engages the under side of a diaphragm 3%, which diaphragm is disposed to be depressed by the spring 33. The spring 33 tends to hold the valve 30 in open position; but when the air pressure in the chamber 29 exceeds the degree for which the spring 33 is adjusted, this pressure, acting upon diaphragm 341:, compresses the spring 33 and permits the valve 30 to close,-all as set forth in said Patent 1,040,070. The chamber 32 is at one end of a passageway 35 (see Fig. 6). This passageway receives air from a passageway 36 whose receiving end is in the chamber 37 which contains the emergency valve 1.5. The passageway 36 is on the brake cylinder side of the check valve 16. then the slide valve is in service position, air from the brake pipe passes through chamber 13, past check valve 16, through passageways 36 and 35, to valve chamber 32, past valve 30 to chamber Q9, through passageway 23 and port 27, passageway 2G in the main slide valve, passageway 22, port 24:', passageway 25, and brake cylinder pipe 19. Pressure cannot escape back into thevbralre pipe from the brake cylinder because of the check valve 16.

The auxiliary reservoir is recharged by means of the passageway 35. As shown by Figs. il and 6, one end of this passageway registers with a port 3S in the slide valve bushing. This port is hereinafter termed the recharging port. lt is disposed to be closed by the slide valve 20 when the latter is in all positions except full release position and one other position which l call semii.elease position. The slide valve is shown in full release or running position by Fig. 2, and in semi-release position by Fig. 3. My reason for using the phrase semi-release is that the brakes are only partly released when the slide valve is in this position, a full release of the brakes being possible only when the slide valve is in the position shown by Fig. 2. The operation by which the brakes are partially released is hereinafter explained.

The slide valve 20 has two recharging ports which are indicated respectively at 39 and 110, and it carries an auxiliary slide valve il which for the salte of avoiding confusion l call a cut-olf valve. The function of the valve al is to cut off coinniunication between the auxiliary reservoir and the recharging passageway upon the `first movement of the main piston Q3 from running position to service position to prevent leakage from the auxiliary reservoir back into the brake pipe should the check valve 1G for any reason be defective or held open by a particle of dirt. |The valve 11 is connected to the stem of the main piston and is moved to the left .from the position shown by Fig. 2 as soon as the main piston begins to move, thus cutting off communication between the auxiliary reservoir and passageway 35 before the piston has picked up the slide valve 20.

The triple valve is provided with two exhaust passageways, one of which, indicated at i2, l call the main exhaust, and the other,

indicated at 13, li call the semi-exhaust. As

shown by Fig. 2, air from the brake cylinder may pass through passageway 25, port 2li, exhaust cavity ahlin the bottom of the slide valve 20, exhaust port L15, and the main exhaust passageway Al2 to the atmosphere. (See Fig. G.) Air can escape at the same time through port 46 into the semi-exhaust passageway This passageway (see Fig. 6) delivers the air into a valve chamber 47 which contains an automatic low pressure retaining valve /18 of well-known construction.

The terms automatic low-pressure retaining valve and retaining valve are synonymous as used in this specification and in the claims, and it is to be understood that the meaning of said terms in every instance is a valve which will retain only a predetermined pressure and permit the'escape of all pressure above such predetermined pressure.

This valve is provided with a weight 49 by which it is normally held seated against `the valve 48 beforethe pressure inthe brake cylinder is reduced to that of the atmos-` phere, the brake cylinder pressure being thereafter fully exhausted by the main exhaust 42 alone. The chief utility of the retaining valve 48 is, however, to hold the brakes applied at relatively low pressure while the auxiliary reservoir is being recharged with the slide valve 20 in the position shown by Fig. 3. In this position the main exhaust port 45 is closed, and the only escape is through the semi-exhaust 43 and retaining valve 48. The slide valve is moved to this position by a very sudden and relatively great increase of brake pipe pressure above the auxiliary reservoir pressure while vthe brakes are applied. This great excess of brake pipe pressure, acting upon the main piston 23, moves the slide valve past full release position and causes the slide valveto compress a spring 5l. spring is compressed between a sliding block 52 and an adjustable bonnet 53. They blockv 52V is normally held against the right-hand end of the bushing 11 with a pressure which may be regulated by adjusting the bonnet 53 to vary the pressure of the. spring. Air passageways 54 are formed in the block 52, its support, and bonnet 53, to conduct the airv to and from the auxiliary reservoir. l/Vhen the valve 20 is in' full release or running position, its right-hand end merely touches the block 52, the latter remaining in the poi sition shown; but when after a brake application the brake pipe pressure is raised more than enough to give a full release, the piston 23 and the valve 2O have an overtravel past running position to the position shown by Fig. 3, thereby displacing the block 52 to the right and compressing the spring 5l. As this cuts oif the main exhaust-42, the air in the .brake cylinder can escape only through the semi-exhaust which is con-I trolled by the retaining valve 48. This valve, as previously stated, does not permit a' full release of the brakes but permits only a semi-release, and holds the brakes'at reduced pressure until the slide valvey 20 is returned to full release position by the Aspring 51.` Such return cannot occur until the auxiliary reservoir pressure has beenv raised to such a point that it in conjunction with the spring 51 is sufficient to predominate over the brake pipe pressure actingupori the left'- hand side ofthe piston 23. .Theu'pressure on through outlets 50, 50. The weight 49 closes (See Fig. 1.) This' soon as the valve 2O is placed in full releasel position, the reduced pressure in the brakel cylinder escapes through the main exhaust 42, and the valve remains in this position until the next reduction of brake pipe pressure. The main exhaust 42 is, of course, momentarily open while the slide valve 2O is moving` from service positian to semi-release position. This momentai y opening of the main" exhaust is an advantage in that it hastens the reduction of brake cylinder pressure to the reduced pressure desired. The pressure which is retained by the valve 48 depends, of course, uponA the size of the weight 49. For ordinary purposes this weight would preferably be of a size sufficient to retain from fifteen to twentyv pounds pressure in the brake cylinder, but could obviously be made to retain a greater pressure or tore-lease the pressure to` a lower` point. Tt has now been shown how the semi-exhaust 43 hastens full releasey of the' brakes and how. the main exhaust 42 hastens the reduction ofpressure to a'seini-release.

Figs. 6 and 7 show a devicefor equalizing auxiliary reservoir pressure and brake pipe y Vlost through the leakage groove of the pis-v ton bushing. The saving of auxiliary reservoir pressure causes the triple valve to act'r more promptly whena service reduction is made. Referring first to Fig. 6, an equalizi'ng valve chamber is indicated at This chamber contains two valve seats, indicated respectively at 56 and 57. A passageway 58 forms communication between thepassage-v way 35 and one end of the chamber 55, while a passageway 59 forms communica-tion be-V tween Vthe other end of the chamber and the auxiliary reservoir through the slide valvel bushing 11. The opening into` the slide valve bushing is above the slide valve and is always open. rlhe valve mechanism which occupies the chamber is shown by Fig. 7, but is omitted from Fig. 6 because the scale of the latter ligure is too much reduced. :is shown by F ig. 7, the valve mechanism comprises a plunger which has a valve 61 at one end and a valve 62 at the opposite end. rllhese valves coperate respectively with the seats and 57. The valves are open as shown by F ig. 7, the plunger 60 being in a neutral position midway between the valve seats. The plunger is provided with equalizing grooves 63 and with an equaliaing pas sageway 6a.- whereby the brake pipe pressure may sustain the pressure in the auxiliary reservoir and compensate for slight leakage. trom the latter. The equalizing chamber is divided by diaphragm 65, the plunger 60 being suitably connected to the diaphragm so as to be actuated in one direction or the other according to a greater air pressure on one side or the other. rllhe engineers feed valve, of course, supplies the entire brake system with air to compensate for slight leaks while the triple valves are in full release or running position, this supply passing to the auxiliary reservoirs of the several cars through the passageways 36, 35, recharging ports 38, and likewise through the eaualizing passageway 6e and grooves 63. lllhenever the brake pipe pressure is reduced suiliciently to effect an application of the brakes, the predominating pressure in the auxiliary reservoir acting upon the. right-hand side of the piston causes the triple valve to operate as usual.

The operations attending a service application are in accordance with standard `practice, as follows auxiliary reservoir air escapes into the brake cylinder so long as the triple valve remains in service position, and when the auxiliary reservoir pressure has dropped slightly below the reduced brake pipe pressure the latter moves the triple piston and graduating pin valve to service lap position. The control of the auxiliary reservoir air is, however', different from that in the standard triple valve, in that no air is permi ted to llow from the auxiliary reservoir to the brake pipe when the service reduction occurs. For this and other reasons a normal running pressure ot' fifty pounds is as effective as a normal running pressure of sixty pounds with triple valves which have a leakage groove in the piston bushing. Assuming, for the sake of illustration but without any idea ot' limiting my invention, that .ifty pounds is the normal running pressure and that reducing the brake pipe pressure to forty-five pounds is suilicient 'for applying the brakes, and assuming also that the brake cylinder supply valve 30 closes when the pressure against the diaphragm Slis at 'forty pounds, the following conditions occur when the triple valve is operated. Starting with the valve in running position with the pressure at titty pounds, the lirst change is a drop of brake pipe pressure to fortydive pounds. rlhe emergency check valve 16 prevents a drop of pressure between it and the auxiliary reservoir, and consequently no air can escape from the auxiliary reservoir into the brake pipe. Incidentally the diaphragm 6o remains balanced, unless, ot' course, the check valve 16 leaks. In the event ot a leak past the check valve, the pressure on the right-hand side oit' the diaphragm 65 will drop, and the valve 61 will thereupon` be closed and prevent the loss of pressure from the auxiliary reservoir at this point. Such closing of the valve 6l will occur, if at all, before the slide valve 20 is moved, because the equalizing valve is so sensitive that it will be operated by a variation ot live or six ounces of pressure, whereas a variation ot' three or four pounds pressure is necessary to move .the slide valve. he triple valve will then move to service position as usual and enable iiuid pressure to pass from the auxiliary reser voir into the brake cylinder and also pass directly from the brake pipe through the reducing valve and passageway 26, into the brake cylinder,-all as set forth in said Patent 1,040,070. The eoualizing passageway and the grooves 63 are so limited in their capacity that a few ounces dillerence in pressure on either side ot' the diaphragm will close the valve on the low-pressure side; and although the pressure in every case will eventually equalize through said port and grooves. the very limited capacity ot the port and grooves retards the equalizing operation. The capacity of these equalizpassa geways is only enough to compensate for unavoidable leakage from the auxiliary reservoir when the triple valve is in running position. So long as the pressures are equal, or nearly so. the device stands in its normal position with both valves open, as shown b v Fig. 7.

lf the brake pipe pressure be increased beyond the capacityV of the euualizing grooves 63 and passageway 64, the valve 62 will be closed `and thus cut oil all communication between the brake pipe and the auxiliary reservoir. inasmuch as five or six ounces excess pressure in the brake pipe will cause the closing of the valve 62, no appreciable quantity of fluid pressure can pass from the brake pipe into the auxiliary reservoir until the slide valve is moved to one of its two recharging positions shown valve in moving from service or service lap position to either' recharging position is easily and quickly effected. If it is desired to eifect a full release of the brakes at once, the brake pipe pressure would be increased only enough to kmove the slide valve to the position shown by Fig. 2. On the other hand, if it should be desired to hold the brakes applied at reduced pressure by the retaining valve 'before effecting a full release, the brake pipe pressure would be increased to a greater extent so as to cause the slide valve to move to the position shown by Fig. 3. The slide valve 20 would remain in semi-release position until the auxiliary reservoir were recharged through the port 39. The slide valve would then move to full release or runningy position, but under no circumstances could the slide valve be shifted from semi-release to full release position without first recharging the auxiliary reservoir to the same pressure as that in the brake pipe.

The operations 'hereinbefore described would not aiect the standard, well-known operation of the emergency valve 15. Fig. 4: shows a'port 70 in the bushing 11' for conducting air from the auxiliaryl reservoir to the emergency piston 14, and Fig. 5 shows a cavityv 71 in the slide valve 2O for uncoveringthe port 'when the slide valv is moved to emergency position.

I am well aware that retaining valves have been used for the purpose of `holding the brakes applied at relatively low pres-'- sure; but I believe I am the first to provide means for automatically effecting a full release of the brakes after the brakes have been held applied at low pressure by a retaining valve. It has been necessary hitherto for trainmen to operate hand valves in order to fully release the'brakes which have been held applied by retaining` valves.

As a result of combining a retaining'valve' with a triple valve and providing connections whereby `the slide valve is adapted to causel ai full release lofthe brakes after the retaining valve has been used, the engineer of a train comprisinga'large number of cars (freight cars, for example) isenabled to release the brakes of the rear cars before the brakes of the forward cars are released. For example, if a train comprises forty cars and the brakes yare held applied while the triple valves arein service lap position, the engineer, wishing to release the brakes on the rear cars rst, does so by admitting a great volume of compressed air from the main reservoir into thebrake pipe.l

The triple valves of the forward cars are influenced to a greater extent than the triple valves' of the rear cars, because they are nearer `the source of supply. The triple valves of the forward cars-the rst twenty cars, for example-will therefore receive excessive pressure which will shift them to semi-release position `(Fig. 3), the `valves4 of the several cars acting successively. As each slide valve comes to recharging position, some of the air passes from the brake pipe into the auxiliary reservoir, and by the time the increased brake pipe pressure has acted uponabout` twenty triple valves` its excessis so much reduced that'thereafter it will move the remaining triple valves only lto full release position. The brakes of the rear cars will thereupon be fully released without anyutilization. of their retaining valves 48. This operation avoids' a common cause of breaking a train'in 'two when the engineeropens the throttle before all the brakes have vbeen released vand 'I believe I am the firstl to have providedre# leasing mechanism whereby the'brakes .on the forward carswill lbe held applied until those on the rear cars havebeen released. If the engineer raises the brake/,pipe pressure only so much as to move"v the `triple valves at the front end of the train to full release position, the brakes will be released at the front end of the train first, regardless of whether the train is longer short.

VIclaim: 'f 1. In a fluid pressure brake apparatus, a triple valve, and an automatic low-pressurev retaining valve arrangedto coact with the.'l

brake cylinder through said triple valve, said triple valve having means, arranged to simultaneously ,vent said brake cylinder through said retaining valvek and form recharging communication between the brake pipe and auxiliary reservoir when out of running position. 'l y 2. In a fluid/pressure brake apparatus,` a triple valve, an automatic low-pressure retaining valve arranged to coact'iwith the brake cylinder through vsaid triple valve, said triple valve having means arranged to simultaneously vent said ybrake cylinder" through said retaining valve and form recharging communication'between the brake pipe and auxiliary reservoir when out of running position,` rand means arranged to vent said brake cylinder independently of said retaining valve when the triple valveis` inl running position. Y'

'3. In a fluid pressure brake apparatus, a brake pipe and a pressure` retaining valve adapted to coact with an'auxiliary reservoir and brake cvlinder, and a triplevalve comprising a slide valve and passageways controlled by said slide valve fory forming communication from said brake cylinder to the atmosphere through said retaining valve I when the brake pipe pressure is above the auxiliary reservoir pressure, and a passageway controlled by said slide valve for forming other communication from said brake cylinder to the atmosphere when the auxiliary reservoir pressure and brake pipe presy sure are equal.

l. In a fluid pressure brake apparatus, a brake pipe and an automatic low-pressure retaining valve arranged to coact with an auxiliary reservoir and brake cylinder respectively, and a triple valve comprising a slide valve, and having passagev-ays controlled by said slide valve for venting said.

brake cylinder through said retaining valve when the brake pipe pressure is above the auxiliary reservoir pressure, a passageway controlled by said slide valve for forming communication between said brake pipe and auxiliary reservoir while said slide valve is adjusted to vent said brake cylinder through said retaining valve as aforesaid, and means controlled bv said triple valve to vent said brake cylinder to the atmosphere independently of said retaining valve.

5. In a fluid pressure brake apparatus,

the` combination with a triple valve arranged to coact with a brake pipe, brake cylinder and auxiliary reservoir, of an automatic low-pressure retaining valve and a passageway leading thereto from the slide valve seat of the triple valve, said triple valve having an exhaust passageway leading directly to the atmosphere from a port in said seat, said slide valve having means for venting said brake cylinder through said retaining valve passageway and retaining valve when the brake pipe pressure is above auxiliary reservoir pressure and for venting said brake cylinder through exhaust passageway when the auxiliary reservoir pressure is built up to the brake pipe pressure.

6. ln a fluid pressure brake apparatus, a brake pipe and an automatic low-pressure retaining valve arranged to coact respectively with an auxiliary reservoir and a brake cylinder, and a triple valve including a main piston movable in both directions from running position, and a valve structure operable by said piston for forming communication between said auxiliary reservoir and brake cylinder when said piston is at one side of said ruiming position and for venting said brake cylinder through said retaining valve when said piston is at 5u the opposite side of said running position.

7. A triple valve for lluid pressure brakes, comprising a main piston and slide valve operated thereby, the seat for said slide valve having a brake cylinder port, an exhaust port, and a third port, all arranged to be controlled by said slide valve, an automatic low-pressure retaining valve and 'passageway leading thereto from said third port, said slide valve having means arranged to vent said brake cylinder through said exhaust port when in running position, and to close said exhaust port and vent said brake cylinder through said third port and retaining valve when behind said running ,65 position.

8. A triple valve for fluid pressure brakes, comprising a main piston and slide valve operated thereby, the seat for said slide valve having a brake cylinder port, an exhaust port, and an intermediate port, and an automatic low-pressure retaining valve arranged to coact with said brake cylinder through said intermediate port, said slide valve being formed to make communication between said brake cylinder port and exhaust port when in running position and to close said communication and vent said brake cylinder through said brake cylinder port, intermediate port, and said low-pressure retaining valve when said slide valve is moved beyond said running position by superior pressure on the brake pipe side of said piston.

9. A, triple valve for fluid pressure brake apparatus including an auxiliary reservoir, said valve comprising a main piston and slide valve operated thereby, the seat for said slide valve having a brake cylinder port and an exhaust port and said slide valve being adapted to form communication between said ports when in ruiming pesition, said slide valve being movable in two directions from running position and adapted to close said communication in any other position, said slide valve seat having a retaining valve port arranged to be controlled by said slide valve and to be in communication with said brake cylinder port when the slide valve is moved past running position by excess pressure on the brake pipe side of' said piston, a low pressure retaining valve and passageway leading thereto from said retaining valve port, and yielding means for coacting with the auxiliary reservoir pressure to move the slide valve to running position.

l0. A triple valve for fluid pressure brake apparatus including an auxiliary reservoir, said valve comprising a main piston and slide valve operated thereby, and a yielding abutment for determining the running position of said piston and slide valve, said abutment being arranged to be displaced by movement of the piston and slide valve bevond running position in the direction away from service position, said abutment being adapted to coact with the auxiliary reservoir pressure to move the piston and slide valve back to running position, the seat for said slide valve having a brake cylinder port, an exhaust port, and a retaining valve port all controlled by said slide valve, and an automatic low pressure retaining valve and passageway leading thereto from said retaining valve port, said slide valve being adapted to form communication from said brake cylinder port to said exhaust port when in running position and to close such communication and vent said brake cylinder through said brake cylinder port, said retaining valve port and said retaining valve when beyond ruiming position toward said abutment.`

11. In a fluid-pressure brake apparatus, an `automatic low-pressure retaining valve arranged to coact with the brake cylinder, and a triplevalve including a main piston and Valve mechanism operable by said piston, said valve mechanism being adapted to vent said brake cylinder through said retaining valve when in anotherposition than service lap position, said valve mechanism being adapted to vent said brake cylinder independently rof said retaining valve when between the two aforesaid positions.

l2. .In a fluid pressure brake apparatus, an automatic low-pressure retaining Valve arranged to coact with the brake cylinder, and a triple valve having a slide valve, a seat for said slide valve, a passageway from said seat to said brake cylinder, a passageway from said seat to said retaining valve, and an exhaust passageway independent of said retaining valve from said seat to thev atmosphere, said slide valve being adapted when in running position to form communication between said three passagcways and in another position to close said exhaust passageway and maintain communication between the two other said passageways.

13. In combination, a triple valve adaptedv to coact with a brake pipe, brake cylinder and auxiliary reservoir of a fluid pressure brake apparatus, and an automatic low-pressure retaining valve arranged to coact with said brake cylinder through said triple valve, said triple valve having means arranged to completely vent said brake cylinder and recharge the auxiliary reservoir when in running position, and to vent said brake cylinder to a predetermined pressure through said retaining valve and recharge said auxiliary reservoir when in anothtr position.

14. A triple valve for coactiug with the brake cylinder of a fluid pressure brake apparatus, and an automatic low-pressure retaining valve arranged to `coact with said bralre cylinder through said triple valve, said triple valve comprising a main piston and means operable by said piston for venting said brake cylinder through said retaining valve, said triple valve having an exhaust port independent of said retaining valve arranged to be put into communication with said brake cylinder through said means when said retaining valve is in communication with said brake cylinder for venting as aforesaid, said means being adapted in one position to close communication between said brake cylinder and exhaust port while maintaining said venting communication through said retaining valve. I l

15. In a fluid pressure brake apparatus,

a .triple valve arranged to coact with the brake cylinder, and an automatic low-pressure retaining valve arranged to coact with said brake cylinder through said triple valve, said triple valve comprising a main piston and valve ymechanism operable thereby, Asaid triple. valve having a passageway V'leading from said valve mechanism` to said brake cylinder, a passageway leading from said valve lmechanism to Vsaid retaining valve, and an exhaust passageway independentof said retaining valve, said valvemechanism when inservice lap position closing said retaining valve passageway and said exhaust passageway, and when in running position forming communication between said three passageways, said piston and valve `mechanism being capable of overtravel beyond running position to a third position in consequence of superior pressure on the brake pipe side of said piston, said valve mechanism being adapted in said third positionto close said exhaust ypassageway and vent said brake cylinder through said retaining valve passageway.

16. In combination, a triple valve and an automatic low-pressure retaining valve in communication therewith for coacting with the brake cylinder of a fluid pressure brake apparatus, said triple valve having an eX- haust port, a brake cylinder port, a port leading to said retaining valve, andvalve mechanism adapted in one position to make communication from said brake cylinder port to said retaining valve port exclusively, and in another position to make communication between all said ports at once.

17. The combination of an automatic lowpressure retaining valve with a tripple valve adapted to coact with a brake pipe, auxiliary reservoir and brake cylinder' of a fluid pressure brake apparatus, said tripple valve comprising a piston and means operable thereby whose traverse in one direction from l running position admits fluid pressure into said brake cylinder, and whose traverse in' the opposite direction from running position vents said brake cylinder through said retaining valve.

18. In a fluid pressure brake apparatus, a triple valve whose pressure-operated parts are movable to both sides of the running position, and an automatic low-pressure retaining valve arranged `to coact with the brake cylinder through lsaid triple valve, said triple valve having passageways controlled by said` pressure-operated parts to charge said brake. cylinder when said parts are at one side of said running position, and a' passageway controlled by said pressure-operated parts to vent said brake vcylinder through said retaining valve when said parts are at the opposite side of said running position.

19. In a fluid pressure brake apparatus, a

triple valve Whose pressure-operated parts are movable to both sides of the running position, and an automatic low-pressure retaining valve aii'ranged tol coact with the brake cylinder through said triple valve, said triple valve having passageways controlled by said pressure-operated parts to charge said brake cylinder when said parts are at one side of said running position, and ports controlled by said pressure-operated parts to Vent said brake cylinder through said retaining valve and recharge the auxiliary reservoir When said parts are at the opposite sides of said running position.

20. In a fluid pressure brake apparatus, a triple Valve, and an automatic low-pres sure retaining valve arranged to coact with the brake cylinder through the slide Valve of said triple Valve, said slide valve having ports arranged to simultaneously Vent said brake cylinder through said retaining Valve Lamas@ and recharge the auxiliary reserif'oir when out of running position.

21. In a fluid pressure brake apparatus, a triple valve, and an automatic low-pressure retaining valve arranged to coaet with the brake cylinder through the slide Valve oi said triple Valve, said triple Valve having ports controlled by said slide Valve to recharge the auxiliary reservoir and vent said brake cylinder to atmospheric pressure When said triple valve is in running position, and ports controlled by said slide valve to recharge said auxiliary reservoir and Vent said brake cylinder through said retaininff valve when in another position.

In testimony whereof I have aflixed my signature, ien presence of two Witnesses.

XVILLIS C. WEBSTER. Witnesses U. S. N. CRoUsE, JAMES M. BRYAN.

Copies of this patent may be obtained for ve cents each., by addressing the Commissioner of Patents. Washington, D. ti. 

